An internal combustion engine generally includes one or more combustion chambers that house a combustion process to produce mechanical work and a flow of exhaust. Each combustion chamber is formed from a cylinder, the top surface of a piston, and the bottom surface of a cylinder head. Air or an air/fuel mixture is directed into the combustion chamber by way of intake ports disposed in the cylinder head, and the resulting exhaust flow is discharged from the combustion chamber by way of exhaust ports also disposed in the cylinder head. Valves are located within the ports of the cylinder head and seal against seats at the entrance of the ports to selectively allow and block the flow of air and exhaust.
Because of the proximity to the combustion process and/or due to friction within the engine, the cylinder head, cylinder liner, and other areas of the engine may be cooled in order to ensure proper and efficient operation of the engine. A cooling system is required to cool fluids directed into or out of the engine and generally includes a heat exchanger. An engine driven fan is disposed either in front of the engine/exchanger package to blow air across the exchanger and the engine, or between the engine and exchanger to blow air past the engine or suck air past the exchanger. In either configuration, a thermostat is located to selectively block the flow of coolant through the engine when the temperature of the engine is too low, and to allow the flow of coolant when the temperature of the engine exceeds a predetermined threshold. This thermostat is generally housed in its own dedicated housing, which can be mounted to the engine block or to the cylinder head. Before or after flowing through the engine, the coolant passes through the thermostat housing.
Although adequate for most situations, the separate thermostat housing can be problematic. Specifically, the separate housing consumes valuable space on the engine and is costly and time-consuming to produce and assemble. In addition, the separate housing introduces opportunities for leaks.
One attempt to solve the problems caused by having a separate thermostat housing is disclosed in U.S. Pat. No. 6,446,586 (the '586 patent) issued to Fukamachi on Sep. 10, 2002. The '586 patent discloses an adjoining engine block and a cylinder head, where both the engine block and the cylinder head have matching overhanging portions. A thermostat housing is fitted between the overhanging portion of the engine block and the overhanging portion of the cylinder head so that it projects from the engine body as little as possible. In this manner, the amount of space consumed by the separate thermostat housing may be minimized.
Although the thermostat housing arrangement of the '586 patent may minimize the amount of engine space consumed, it may still be a separate housing. Therefore, the thermostat housing may still be expensive to produce, time-consuming to assemble, and may provide leakage opportunities.
The present disclosure is directed to overcoming one or more of the shortcomings set forth above and/or other deficiencies in the art.